(NaturalNews) Perhaps the only thing more pervasively toxic than crop chemicals, like glyphosate (Roundup) and atrazine, is these poisons combined with one another. A new study published in the journal Chemosphere has revealed that the amalgamated toxicity of certain pesticides and herbicides increases substantially in comparison to the toxicity of these same chemicals individually.

To make this discovery, researchers from France tested the cytogenetic effects of both glyphosate and atrazine, as well as their degradation products, aminomethyl phosphoric acid (AMPA) and desethyl-atrazine (DEA). Using an in vitro micronucleus assay, the team tested various mixtures of the chemicals on CHO-K1 cells, which were originally derived from hamsters.

Since most chemicals currently in use were only safety tested in isolation -- if they were even safety tested at all -- the team from the Aix-Marseille University (AMU) Laboratoire de Mutagenese et Toxicologie Environnementales decided to look at the combined effects of two of the most common chemical compounds applied to conventional agriculture.

They found that, depending on their unique physico-chemical environment, pesticides vary in their degrees of toxicity. When all four of the tested compounds were combined, for instance, the resultant mixture was determined to have a 20-fold higher level of toxicity in comparison with the active compound AMPA in isolation, which is considered to be the most active of the four compounds.

"Intracellular ROS (review of systems) assessment suggested the involvement of oxidative stress in the genotoxic impact of pesticides and pesticide mixtures," reads the study's abstract.

More concerning was the observed toxicity of these same chemicals with regards to radiation exposure. As it turns out, exposing the chemical cocktail to irradiation from light increased its toxicity 100-fold, meaning that the chemicals became 100 times more toxic as a result.

The implications of this for fruits, vegetables, grains and other foods commonly sprayed with crop chemicals are disconcerting. With the U.S. Food and Drug Administration (FDA) pushing for more irradiation of the nation's food supply, the suggestion here is that any chemical residues present on such food will only become that much more toxic after being irradiated.

These findings also draw attention to the failed government testing requirements for chemicals, which completely disregard any synergistic impact that may result from exposure to multiple chemicals as they exist in the real world, as opposed to individual chemicals as they exist in a testing lab. Evaluating chemicals in isolation only simply does not take into account the thousands of other chemicals to which people are also routinely exposed.

"[This study] highlighted the importance of cocktail effects in environmental matrices," adds the abstract, "and pointed out the limits of usual testing strategies based on individual molecules, to efficiently estimated environmental risks."

Similar research published earlier this year, also out of France, revealed that many pesticide formulas are far more toxic than just their active ingredients. Monsanto's Roundup formula, for instance, is loaded with so-called "inert" ingredients that amplify its toxicity in ways that have never been evaluated in safety studies.